Underreamer.



\ ,PATENTED JUNE 9, 1903.

E. STRIGKLAND.

UNDERRBAM,ER. APPLICATION FILED SEPT. 25, 1902.

2 SHEETS-SHEET 1.

N0 MODEL.

3] n uaufoz THE cams PETERS 5 v PATENTED JUNE 9', 190a.

' E. STRIGKLAND. UNDERREAMER.

I APPLICATION FILED SEPT. 25, 1902, V 110 MODEL 2 SHEETS-8HBET 2.

UNITED STATES Patented dune 9, i903.

PATENT OFFICE.

UNDERREAIVI ER.

SPECIFICATION forming part of Letters Patent No. 730,415, dated June 9,1903.

Application filed September 25, 1902. Serial No. 124,793. fir man.)

To all whom it may concern.-

lie it known that I, ELWIN STRICKLAND, a citizen of the United States,residing at Los Angeles, county of Los Angeles, State of Cali-- fornla,have invented certain new and useful; Improvements in Underreamers; andI here by declare the following to be a full, clear, and exactdescription of the same, reference being had to the accompanyingdrawings, in which- Figure 1 is a partial central section of anunderreamer embodying my invention, the operative parts being inelevation and the cutters expanded. Fig. 2 is a bottom plan view ofFig. 1. Fig. 3 is a partial centralsec-. tion, the operative parts inelevation and the cutters closed or withdrawn for insertion in:

Fig. 4 is a bottom plan View ofthe casing. Fig. 3. Fig. 5 is an enlargedlongitudinal central section of the lower member of the stock, thecutters being removed.

member of the stock, the cutters being removed. Fig. 7 is an enlargeddetached View in elevation and bottom plan of the camthe arrow d, Figs.8 and 11.

Like symbols refer to like parts wherever they occur.

My invention relates to the construction of that class of devices termedunderreamers, which are employed for enlarging the diameter of Artesianwells where casing is required and the drilling is done through thecasing.

In this class of devices it is essential that they be capable of beinginserted and withdrawn through the casing, for which purpose the cuttersmust be adapted to close and to be expanded, and the cutters must be sosup- 7 Fig. 6 is: an enlarged bottom plan'view of the lower I Fig. 13isan' enlarged view of the opposite side from that; shown in Fig. 12looking in the direction of ported by the stock as to relieve the pivotof undue, strains and leverage, while the stock should, preferably,sustain the force of the blow on lines parallel to the axis thereof.

In carrying out my invention and in order to obtain thehereinbefore-recitedresults in an underreamer, I combine with a stockcrossedand interlocked pivoted cutters, (shear cutters,) the arms ofwhich are received within a chamber, upon the inner walls of which theyfind seats or bearings, said arms provided with shoulders which engagethe bottom of the stock, so that the pivot is relieved of strain and theforce of the blow is transmitted to the stock on lines parallel to itsaxis, and such a'construction embodies the main feature of my invention.

There are other minor features of invention which involve particularfeatures of construction and combinations dependent thereon, all as willbe hereinafter more fully stem and with a wrench-seat 1 for applyingawrench for eifecting said connection as well as the connection betweenthe members A B.

The interior of the box 1 is extended centrally, as at 3, to accommodatethe upper end of a pull-rod and the nut thereon.

The lower member B of the stock has the pin 2, as before noted, forconnecting it with l the member A and below the same a wrenchcutters.Extending downwardly from the bottom of the stock on opposite sides arethe parallel perforated pivot-lugs 7, which not only afford support tothe pivot of the crossed cutters, but also lateral support to thecutters themselves.

8 8 indicate the two cutters, oppositely disposed and provided with arms8, which cross and interlock at the pivot, being provided for thatpurpose with the recesses 8". The shoulders 8 are arcs struck on acircle having the pivot for its center to correspond with the circularedge 7 of the pivot-lugs 7, and thus permit the expansion and closing ofthe cutters, while the shoulder 8 opposite the areshaped shoulders 8 isso shaped as to permit the approach of the arms 8 (see Fig. 3) when thetool is to be introduced or withdrawn through the casing. Each of saidcutters is provided on its exterior with a shoulder 8, adapted to engagethe bottom of the stock between the pivot-lugs 7 when the cutters areexpanded,(see Fig. 1,) and also with the outer bearing-face 8 on the arm8? above the pivotpoint where the arms extend up into the chamber 5 toengage or bear against the inner wall of the chamber 5, and saidshoulders 8 and bearing-faces 8 of the arms, by reason of the cuttersbeing crossed and interlocked, relieve the cutter-pivot 9 of strain andtransfer the force of the blows from the cutters to the stock on linesparallel to the axis thereof. The arms 8 above the pivot are eachprovided with a slot 8 for the reception of a cam-head on the lower endof a spring-actuated pullrod, the function of which (see Fig. l) is tocause the projection of the cutters and force and maintain thebearing-faces 8* of the arms 8 in contact with the inner walls of thechamber 5 of the stock during the operation of the underreamer. For saidpurpose the upper wall of the slot 8 is preferably rounded or cam-faced,(as best shown by the dotted lines, Figs. 11 and 12,) and the slot issufficiently deep to accommodate the descent of the camhead of thepull-rod (see Fig. 3) when the cutters are withdrawn for passing thedevices into and through the casing.

10 indicates a pull-rod, provided at its lower end with a cam-head 10,of general triangular form, adapted by its opposite arms to engage inthe cam-slots 8 in the arms 8 of the cutters 8. This pull-rod occupiesthe axis of the stock and extends from lower chamber 5 thereof throughpassage 6 into upper or spring chamber 4, where it is encircled by aspiral spring 11, the upper threaded end of said pull-rod 10 beingprovided with a nut 12, which confines the pull-rod, bears on the upperend of the spring, and may be manipulated to increase or decrease theforce exerted by the spring on the pull-rod and through said pull-rodon-the arms 8 of the cutters 8 above the pivot 9 thereof.

The construction of the several parts of the underreamer beingsubstantially such as here inbefore pointed out, the parts maybe assembled by first crossing and interlocking the arms 8 of the cutters 8,then with the cutters expanded introducing the cam -head 10 of pull-rod10 into the cam-slots 8 of the cutterarms 8*, next closing the cutterarms (see Fig. and introducing the pull-rod and cutter-arms 8 axiallyinto the stock until the pivot 9 can be inserted through the pivotholesoi dependent lugs 7 and through the cutters, after which the spiralspring 11 may be introduced into chamber 4 around the pull-rod and thenut 12 applied to said pullrod to confine it and the spiral spring, and,finally, the members A and B of the stock maybe screwed together,whichcompletes the device.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is

1. In an underreamer,the combination with a cutter-stock havinga cavityat its lower end, of crossed and interlocked cutters pivoted on thestock and having shoulders which engage the lower end of the stock andarms which extend into and engage the inner walls of the stock,substantially as and for the purposes specified.

2. In an underreamer,the combination with a cutter-stock having a cavityat its lower end, of crossed and interlocked pivoted cutters havingshoulders which engage the cutterstock in the plane of the pivot andarms above the pivot which extend into the cavity of the cutter-stock,substantially as and for the purposes specified.

3. In an underreamer,the combination with a cutter-stock having a cavityat its lower end, of crossed and interlocked cutters pivoted on thecutter-stock having shoulders which engage the cutter-stock and armswhich extend into the cutter-stock, and means for exerting a yieldingtension on the arms of the cutters above the pivot, substantially as andfor the purposes specified.

4.. In an underreamer,the combination with a cutter-stock having acavity in its lower end, of crossed and pivoted cutters having shouldersWhich engage the cutter-stock and arms which extend into the cavity ofthe cutterstock, and a spring actuated pullrod connected with the armsof the cutters above the pivot, substantially as and for the purposesspecified.

5. In an underreamer,the combination with a cutter-stock, of crossed andpivoted cutters having cam-slots above the pivot thereof, andaspring-actuated pull-rod having acamhead which engages the cam-slots ofthe cut-' ters, substantially as and for the purposes specified.

6. In an underreamer,the combination with a separable cutter-stock, thelower member of which has an axially-disposed spring-cham- In testimonywhereof I affix my signature, in presence of two witnesses, this 13thday of 10 September, 1902.

ELWIN STRIOKLAND.

Witnesses: I

WILLIAM H. EASTMAN, HOWARD A. THORNTON.

